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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hapten (DNP-lys) conjugates of two putatively nonimmunogenic polymers, hyalutonic acid and poly-gamma-D-glutamic acid, induce significant primary IgM anti-DNP responses in C3H mice. Preparations of various immunogenic (Type 3 pneumococcal polysaccharide (SIII), levan, E. coli lipopolysaccharide) and nonimmunogenic (hyaluronic acid and poly-glutamic acid) polymers were tested for their ability to act as polyclonal mitogens in vitro. In serum-containing spleen cell cultures, only lipopolysaccharide stimulated substantial cell proliferation. In serum-free medium, and using high specific activity [3H]thymidine, lipopolysaccharide, levan, SIII and to a lesser degree hyaluronic acid induced significant thymidine incorporation. However, under the latter conditions cell survival and proliferation were much less impressive. There was no apparent correlation between the capacity of various polymers to induce lymphocyte proliferation and their "potency" as carriers for the generation of a primary IgM anti-DNP response. Furthermore while low doses of lipopolysaccharide elicited "polyclonal" antibody formation in vivo, high doses of SIII, levan and hyaluronic acid did not. These results indicate that T cell-independent B cell triggering is dependent on the polymeric nature of the antigen, and that polymers need not be immunogenic or mitogenic to act as carriers for the induction of primary IgM anti-hapten antibody responses.
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PMID:The immunological properties of haptens coupled to thymus-independent carrier molecules. III. The role of the immunogenicity and mitogenicity of the carrier in the induction of primary IgM anti-hapten responses. 1 Jan 66

1. Protein extracts obtained from Salmonella minnesota Re mutant cells by treatment with EDTA/NaC1 solution contain a protein which exhibits high affinity to bacterial lipopolysaccharides. The isolation and partial characterization of this lipopolysaccharide-binding protein is described. 2. The protein was purified from EDTA extracts by a two-step procedure consisting of ion-exchange chromatography on CM-Sephadex and preparative polyacrylamide gel electrophoresis at pH 9.5. The yield of the total purification procedure was around 16%. 3. The resulting protein preparation was homogeneous on the basis of disc gel electrophoresis, dodecylsulfate gel electrophoresis, isoelectric focusing in polyacrylamide gel and immunoelectrophoresis. 4. The isoelectric point of the protein was found to be 10.3 at 4 degrees C. Its molecular weight determined by dodecylsulfate gel electrophoresis is 15000. Its amino acid composition is characterized by the absence of histidine and proline, a low content in tyrosine and high amounts of alanine, lysine, aspartic and glutamic acid residues, or their respective amides. 5. The lipopolysaccharide-protein association was shown to be mainly due to ionic interactions of the basic protein with negatively charged groups (probably phosphate and pyrophosphate groups) of the lipid A moiety. 6. Purified lipopolysaccharide-binding protein is immunogenic in rabbits, thus enabling the preparation of specific antiserum. 7. The protein is located at the surface of Salmonella minnesota Re mutant cells as revealed by antiserum absorption with total bacteria. Ferritin-labelling studies further demonstrated that it is evenly spread over the entire cell surface. 8. Comparative antiserum absorption studies using smooth and rough strains of Salmonella minnesota, Salmonella typhimurium, Escherichia coli, Klebsiella and Shigella revealed the presence of lipopolysaccharide-binding protein (or a serologically cross-reacting antigen) in most of the strains tested. From these results the protein can be considered as a common antigen of Enterobacteriaceae.
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PMID:A lipopolysaccharide-binding cell-surface protein from Salmonella minnesota. Isolation, partial characterization and occurrence in different Enterobacteriaceae. 11 33

Dinitrophenyl (DNP)-lysine-polymethylmethacrylate and DNP-cellulose conjugates do not irreversibly inactivate anti-DNP antigen-sensitive cells, regardless of the dose (up to 10 mg) or persistence of the stimulation (up to 2 weeks). Since these conjugates constitute pure hapten presentations, it is concluded that the pure hapten presentation to B lymphocyte does not irreversibly inactivate them. When murine spleen cells are cultured with Escherichia coli lipopolysaccharide (LPS) and (non-immunogenic) DNP-lysine-polymethylmethacrylate or (non-immunogenic) DNP-cellulose conjugates, an anti-DNP immune response occurs. However, replacement of DNP-lysine-polymethylmethacrylate with polymethylmethacrylate, or DNP-cellulose with cellulose, also results in a similar anti-DNP response. It is consequently concluded that the anti-DNP responses are entirely elicited by LPS, the hapten Dnp being inoperative. The anti-DNP response elicited by DNP-Ficoll is, upon exhaustive testing, carrier-dependent. This implies that the mechanism of DNP-Ficoll immunogenicity is not two cooperative signals passed on to B lymphocytes via the hapten DNP. These results argue against any two-signal model of B-lymphocyte activation.
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PMID:A chemical approach to the mechanism of B-lymphocyte activation. II. The pure presentation of haptens does not inactivate B lymphocytes. 30 27

Lipopolysaccharides of qualitatively identical but quantitatively different sugar composition were extracted from Proteus mirabilis strain 1959. The lipopolysaccharide with the higher percentage of typical O-specific constituents was subjected to partial acid hydrolysis. An oligosaccharide B22 was separated by paper chromatography and electrophoresis. It was found to be composed of equimolar amounts of D-galacturonic acid, D-galactosamine and L-lysine. Dinitrophenylation of the oligosaccharide as well as of the genuine lipopolysaccharide afforded xi-dinitrophenyl-L-lysine after acid hydrolysis, showing that lysine was linked to the disaccharide via its alpha-amino group. Further studies including the Morgan-Elson and Elson-Morgan reactions, NaBH4-reduction, hydrazinolysis and periodate oxidation revealed the structure of oligosaccharide B22 as D-galacturonyl-(1 leads to 4)-D-galactosamine with lysine attached to the carboxylic group of galacturonic acid via its alpha-amino group. Judged from its high inhibition capacity this oligosaccharide has to be considered as an essential part of the serological determinant of Proteus mirabilis 1959. The frequent occurrence of lysine and galacturonic acid in Proteus mirabilis O-serogroups and their possible significance for the respective serological specificities are discussed.
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PMID:The linkage of lysine in the O-specific chains of Proteus mirabilis 1959. 76 6

The effect of endotoxin or lipopolysaccharide (LPS) on tolerance induction in bone marrow-derived lymphoid cells (B cells) was investigated. Dinitrophenylated amino acid copolymer-L-(glutamic acid, lysine) (DNP-GL) acts as a potent tolerogen on normal and DNP-primed B cells. LPS significantly enhanced the anti-sheep red blood cell plaque-forming cell (anti-SRBC PFC) response that occurred after the immunization with a low dose of SRBC. LPS did not induce the primary anti-DNP PFC response after the injection of DNP-GL, nor did it prevent the tolerance induction in normal and DNP-primed B cells that occured after the administration of DNP-GL.
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PMID:Ineffectiveness of lipopolysaccharide for preventing the tolerance induction in bone marrow-derived lymphoid cells with dinitrophenyl-poly-L-(glutamic acid, lysine). 79 34

Immunostimulated peritoneal macrophages of mice and rat have been demonstrated to produce L-arginine-derived nitrogen oxides. This metabolic pathway has also recently been found in rat alveolar macrophages and is suggested to play a certain role in lung injury. In vitro nitrite production from alveolar macrophages stimulated in vitro with lipopolysaccharide and recombinant interferon-gamma was inhibited by the addition of the irreversible serine-protease inhibitors, N-tosyl-L-phenylalanine chloromethyl-ketone (3 x 10(-7)-3 x 10(-4) M) and N-tosyl-L-lysine chloromethyl-ketone (3 x 10(-7)-3 x 10(-4) M) in a concentration-dependent manner. Two reversible inhibitors, N-alpha-p-tosyl-L-arginine methyl ester hydrochloride and benzoyltyrosine ethyl ester, were also effective but to a lesser extent. These antiproteases provide an opportunity to study the modulating influence on this recently discovered inflammatory pathway in alveolar phagocytic cells.
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PMID:Serine-protease inhibitors modulate nitric oxide-synthase activity of alveolar macrophages. 138 78

Black lipid membranes were formed of tetraether lipids from Thermoplasma acidophilum and compared to the bilayer forming lipids diphytanoylphosphatidylcholine and diphythanylglucosylglycerol. Bilayer-forming lipids varied in thickness of black lipid membranes due to the organic solvent used. Measurements of the specific membrane capacitance (Cm = 0.744 microF/cm2) showed that the membrane-spanning tetraether lipids from Thermoplasma acidophilum form a monolayer of a constant thickness of 2.5-3.0 nm no matter from which solvent. This finding corresponds to the results of Gliozzi et al. for the lipids of another archaebacterium, Sulfolobus solfataricus. Black lipid membranes were formed at room temperature with a torus from bilayer-forming lipids, however, the torus could also be formed by the tetraether-lipid itself at room temperature and at defined concentration. In these stable black lipid membranes, conductance was measured in the presence of valinomycin, nonactin, and gramicidin. At 10(-7) M concentration, valinomycin mediated higher conductance in membranes from tetraether lipids (200-1200 microS/cm2) than from bilayer-forming lipids (125-480 microS/cm2). Nonactin, at 10(-6) M concentration, mediated a 6-fold higher conductance in a tetraether lipid membrane than in a bilayer, whereas conductance, in the presence of 5 x 10(-11) M gramicidin could reach higher values in bilayers than in tetraether lipid monolayers of comparable thickness. Monensin did not increase the conductance of black lipid membranes from tetraether lipids under all conditions applied in our experiments. Poly(L-lysine) destroyed black lipid membranes. Lipopolysaccharides from Thermoplasma acidophilum were not able to form stable black lipid membranes by themselves. The lipopolysaccharide complexes from Thermoplasma acidophilum and from Escherichia coli decreased the valinomycin-mediated conductance of monolayer and bilayer membranes. This influence was stronger than that of the polysaccharide dextran.
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PMID:Black lipid membranes of tetraether lipids from Thermoplasma acidophilum. 142 Feb 95

Escherichia coli strains of serogroup O115:K(-):F165 have been associated with septicemia in calves and piglets. These strains express a capsular antigen referred to as K"V165" which inhibits agglutination of the O antigen by anti-O115 serum. We used hybrid transposon TnphoA mutants M48, 18b, and 2, and a spontaneous O-agglutinable mutant, 5131a, to evaluate the role of K"V165" in the pathogenicity of E. coli O115. Mutant M48 was as resistant to 90% rabbit serum and as virulent in day-old chickens as the parent strain 5131, mutants 18b and 5131a were less resistant to serum and less virulent in chickens, and mutant 2 was serum sensitive and avirulent. Analysis of outer membrane protein and lipopolysaccharide profiles failed to show any difference between the transposon mutants and the parent strain. In contrast, the spontaneous O-agglutinable mutant showed additional bands in the 16-kDa region of the polysaccharide ladder-like pattern. Mutants 2 and 5131a produced significantly less K"V165" capsular antigen than the parent strain, as demonstrated by a competitive enzyme-linked immunosorbent assay with adsorbed anti-K"V165" serum. In addition, electron microscopic analysis revealed that mutants 2 and 5131a had lost the capsular layer observed in the parent strain after fixation with glutaraldehyde-lysine. This capsule contained carbohydrate compounds and resembled an O-antigen capsule since it prevented O-antigen agglutination before the bacteria were heated at 100 degrees C and induced bacterial serum resistance. The capsule-defective mutants colonized the intestinal epithelium of experimentally infected gnotobiotic pigs but failed to induce clinical signs of septicemia. We concluded that E. coli strains of serogroup O115 expressed a polysaccharide capsular antigen which induced serum resistance and consequently contributed to the pathogenicity of the bacteria.
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PMID:Characterization of a polysaccharide capsular antigen of septicemic Escherichia coli O115:K "V165" :F165 and evaluation of its role in pathogenicity. 145 37

Transport of L-arginine and nitrite production were examined in the murine macrophage cell line J774. Bacterial lipopolysaccharide (LPS) induced a dose- and time-dependent stimulation of nitrite production, which was further increased in the presence of interferon-gamma. Nitrite synthesis was absolutely dependent on extracellular L-arginine and inhibited in the presence of L-lysine or L-ornithine. In unactivated J774 cells L-arginine transport was saturable, with an apparent Km of 0.14 +/- 0.04 mM and Vmax. of 15 +/- 2 nmol/h per 10(6) cells. LPS (1 microgram/ml) induced a time-dependent stimulation of L-arginine transport, and after 24 h the Vmax. increased to 34 +/- 2 nmol/h per 10(6) cells. These findings indicate that activation of J774 cells with LPS produces an increase in both L-arginine transport and nitrite synthesis. The elevated rate of L-arginine transport in activated J774 cells may provide a mechanism for sustained substrate supply during enhanced utilization of L-arginine for the generation of NO.
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PMID:L-arginine transport is increased in macrophages generating nitric oxide. 159 94

Routes of quinolone permeation in Pseudomonas aeruginosa were investigated by using sparfloxacin as a prototype compound. [14C]sparfloxacin cell labeling was 13 to 28% lower in three protein D2-deficient mutants resistant to imipenem than in their imipenem-susceptible counterparts. In four impermeability-type quinolone-resistant strains isolated from pefloxacin-treated animals, we observed two- to fourfold-greater resistance to imipenem, reduced protein D2 expression in the outer membrane according to Western blotting (immunoblotting), and 25 to 29% decreased cell labeling with imipenem. In a protein D2-producing strain but not in its protein D2-deficient isogenic mutant, uptake of [14C]sparfloxacin was strongly inhibited by L-lysine and imipenem, which act as substrates for protein D2. Conversely, binding of [14C]imipenem in a porin D2-positive strain was reduced by sparfloxacin but not by the nonamphoteric quinolone nalidixic acid. Sparfloxacin, imipenem, and lysine possess a carboxyl group and a potentially protonated nitrogen separated from each other by 0.64 to 1.07 nm as calculated by computer. Hence, protein D2 may catalyze facilitated diffusion for sparfloxacin, as it does for imipenem. In addition, pefloxacin-selected isolates contained 41 to 113% more 3-deoxy-D-mannooctulosonic acid than their quinolone-susceptible counterparts, with MIC increases of 2- to 4-fold for WIN-57273 (n-octanol-phosphate buffer partition coefficient, 13.139), 4- to 8-fold for difloxacin (partition coefficient, 3.093) and sparfloxacin (partition coefficient, 0.431), and 8- to 16-fold for norfloxacin (partition coefficient, 0.059) and ciprofloxacin (partition coefficient, 0.056). Thus, we hypothetize that in quinolone-selected strains, increased amounts of lipopolysaccharide form a permeability barrier that acts preferentially against hydrophilic quinolones.
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PMID:Role of protein D2 and lipopolysaccharide in diffusion of quinolones through the outer membrane of Pseudomonas aeruginosa. 166 23


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